Vapor control system for an underground storage tank

ABSTRACT

A vapor control system for an underground storage tank for gasoline or the like. In this system the underground tank is provided with a vent pipe having its discharge end disposed within an exhaust chamber arranged closely adjacent the ground. This eliminates the conventional comparatively tall vent stack which permits air to escape into the atmosphere as the underground storage tank is filled with gasoline or the like. The vapor control system also includes a vapor discharge pipe that extends from the underground storage tank to the interior of the delivery truck to transfer vapors displaced from the tank into the truck as the tank is filled by the truck.

United States Patent Turner [4 May 16, 1972 [541 VAPOR CONTROL SYSTEM FOR AN 3,016,928 l/l962 Brandt ..141/290 NDER D ST RA E 1 U GROUN O G TANK FOREIGN PATENTS OR APPLICATIONS [72] Invent g g 2 $22?" 1,301,459 7/1962 France. 141/290 eac a I 119,493 8/1947 Sweden 141/290 [22] Filed: Nov. 23, 1970 Primary Examiner-Houston 5. Bell, Jr. 1 PP 911719 ArtorneyFulwider, Patton, Rieber, Lee & Utecht 52 U.S. c1 ..141/290, 137/587, 222/481.5 [57] ABSTRAeT [51] Int. Cl ..B65h 39/04 A vapor control system for an underground storage tank for [58] Field of Search .;.l4l/4, 5, ll, 37, 44, 45, 46, gasoline or the like. In this system the underground tank is 141/47, 48, 49, 50, 52, 53, 54, 55, 59, 60, 99, 290, provided with a vent pipe having its discharge end disposed 300 303 307 309 310; 222/1 3, 4315; 137/583, within an exhaust chamber arranged closely adjacent the 587, 588; 220/44 3, 44 A ground. This eliminates the conventional comparatively tall vent stack which permits air to escape into the atmosphere as 56.] Referen e Ci d the underground storage tank is filled with gasoline or the like. The vapor control system also includes a vapor discharge pipe UNITED STATES PATENTS that extends from the underground storage tank to the interior of the delivery truck to transfer vapors displaced from the Gosselln tank i the truck as the tank is the truck. 2,928,436 3/1960 Wendrow et al...

2,939,611 6/1960 Nebinger ..222/4815 5 Claims, 3 Drawing Figures Patented May 16, 1972 3,662,794

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INVENTOR. Dav/v5 .51 TUBA/5Q Arraxewzrs VAPOR CONTROL SYSTEM FOR AN UNDERGROUND STORAGE TANK BACKGROUND OF THE INVENTION The conventional underground gasoline storage tank as used at service stations is provided with a vent stack for exhaustihg air into the atmosphere as the storage tank is filled. Such vent stacks are comparatively expensive to construct and maintain. Additionally, the escaping gasoline vapors present a serious fire hazard. Moreover, the discharge of such vapors into the atmosphere is a serious source of air pollution.

SUMMARY OF THE INVENTION The vapor control system of the present invention eliminates the usual vent stack of an underground storage tank and additionally prevents discharge of vapors into the atmosphere as the tank is being filled. A short vent pipe is substituted for the usual vent stack, with the discharge end of such vent pipe being disposed within an exhaust chamber that is closely adjacent to the ground level. Accordingly, the cost of constructing and maintaining the usual vent stack is eliminated. The present vapor control system also includes a vapor discharge pipe that extends from the upper portion of the underground storage tank to the gasoline delivery vessel so as to transfer the vapors displaced from the underground tank into the vessel as the gasoline is introduced into the tank through the usual inlet conduit. Accordingly, the vapor which normally escapes into the atmosphere when the underground storage tank is filled is instead returned to the delivery vessel. A valve in the vent pipe blocks such vapor from entering the atmosphere, but automatically opens to vent air into the tank as gasoline is withdrawn therefrom.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view showing a conventional underground fuel storage tank during the filling thereof;

FIG. 2 is a side elevational view of a preferred form of vapor control system embodying the present invention; and

FIG. 3 is a central vertical sectional view showing the discharge end of the vent pipe of the system of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings and particularly FIG. 1 thereof, there is shown a prior art conventional underground storage tank S receiving gasoline or other volatile liquid from a delivery truck D. The underground storage tank S is provided with the usual vent stack 10. Storage tank S is also provided with the usual liquid inlet pipe 12 disposed within a manhole 14. The delivery truck D is provided with a tank 15 to which is attached to the usual flexible discharge hose or conduit 18 by means of a suitable pump (not shown). Conduit 18 is connected to the top of the inlet pipe 12 within the manhole 14. When gasoline or the like is discharged from the delivery truck D into the underground storage tank S, the vapors contained within the storage tank will be progressively urged upwardly within the confines of the tank and out of the top of the vent stack 10. The escape of such vapors presents a fire and explosion hazard. This is particularly true where such vapors can collect within a confined space. Additionally, the discharge of these vapors into the atmosphere adds to air pollution.

Referring now to FIG. 2 there is shown a preferred form of vapor control system embodying the present invention. The underground storage tank S-l shown in FIG. 2 does not utilize the conventional vent stack 10 shown in FIG. 1. Instead, tank 5-1 is provided with a short vent pipe 20 which terminates at its upper end in a generally inverted U-shaped discharge fitting F disposed within a manhole 21. The tank 8-] is also provided with a liquid inlet pipe 22 similar to that shown in FIG. 1 disposed within manhole 21. Gravel 23 or the like may be provided for the lower end of manhole 21 to permit water v connected to a flexible hose or discharge conduit 26 that extends from tank 27 of a gasoline delivery truck D-l within the manhole 24. The tank 8-1 is additionally provided with a vapor discharge pipe 28 which extends from the upper portion of the tank into the manhole 24. The upper end of the vapor discharge pipe 28 is adapted to be connected to a flexible hose or conduit 30 that extends from the delivery truck D-l adjacent discharge conduit 26. The upper end of conduit 30 is in communication with the upper portion of the tank 27.

Referring now to FIG. 3, the discharge fitting F includes a downwardly opening branch 34 which is secured to the upper end of vent pipe 20, a horizontal intermediate portion 36 and a downwardly opening branch 38. The lower end of element 38 is provided with a valve body 40 formed at its upper end with a valve seat 42. The valve body 40 includes a plurality of spider elements 44 which support the stem 46 of a poppet valve 48. The poppet valve 48 is biased downwardly to a closed position against the seat 42 by a spring 50. A screen 52 covers the lower end of element 38.

In the operation of the valve control system shown in FIGS. 2 and 3, during loading of the underground storage tank 8-1 from the delivery truck D-l, liquid will flow from the truck and into the bottom of the tank through discharge conduit 26 and inlet pipe 22. As the liquid level within tank S-l rises, the vapors forced upwardly by the rising liquid flow out of the tank S-l through vapor discharge pipe 28 and flexible conduit 30 into the upper confines of the tank 27 of truck D-l. Accordingly, such vapors will not escape into the atmosphere and instead will be trapped within tank 27 for subsequent release into a suitable receptacle (not shown). The conduits 26 and 30 will be disconnected from pipes 22 and 28, respectively, when the tank S-l has been filled, and the pipes will be capped in a conventional manner.

When liquid is removed from the tank 5-1, as for example through the usual gasoline pumps of a service station, the air necessary to replace the removed liquids will enter the upper end of the tank S-l through vent pipe 20 and its fitting F. Such flow of air through fitting F takes place when the pressure differential within the tank and the atmosphere causes the poppet valve 48 to be raised against the pressure of spring 50. The interior of manhole 21 is of course in communication with the atmosphere. Any water which might enter manhole 21 is prevented from entering vent pipe 20 because of the configuration of fitting F.

Referring again to FIG. 2 a conventional gasoline vapor sensing device V may be positioned within manhole 21 to sense any vapor leakage through vent pipe 20 and fitting F in the event the poppet valve 48 should for some reason fail to close. A suitable alarm (not shown) is actuated by vapor sensing device V.

Various modifications and changes may be made with respect to the detailed foregoing detailed description without departing from the spirit of the present invention.

I claim:

1. A vapor control system for an underground storage tank and a movable delivery vessel of a volatile liquid, comprising:

a vent pipe for said tank, said vent pipe having a discharge end disposed closely adjacent the ground level;

a liquid inlet pipe on said tank that is connected to said delivery vessel to transfer said liquid from said vessel into said tank;

a vapor discharge pipe extending from the upper portion of said tank that is connected to said delivery vessel to transfer into said delivery vessel the vapors displaced from said tank as said liquid is introduced into said tank through said inlet pipe; and

valve means controlling flow through said vent pipe, said valve means automatically opening when said liquid is withdrawn from said tank to admit air into said tank as said liquid is removed.

2. A vapor control system as set forth in claim 1 wherein a vapor sensing device is disposed adjacent said vent pipe to detect escape of said volatile liquid.

LII

said vent pipe to detect escape of said volatile liquid.

5. A vapor control system as set forth in claim 4 wherein the upper end of said vent pipe is provided with a generally inverted U-shaped fitting and said valve means is carried by said fitting. 

1. A vapor control system for an underground storage tank and a movable delivery vessel of a volatile liquid, comprising: a vent pipe for said tank, said vent pipe having a discharge end disposed closely adjacent the ground level; a liquid inlet pipe on said tank that is connected to said delivery vessel to transfer said liquid from said vessel into said tank; a vapor discharge pipe extending from the upper portion of said tank that is connected to said delivery vessel to transfer into said delivery vessel the vapors displaced from said tank as said liquid is introduced into said tank through said inlet pipe; and valve means controlling flow through said vent pipe, said valve means automatically opening when said liquid is withdrawn from said tank to admit air into said tank as said liquid is removed.
 2. A vapor control system as set forth in claim 1 wherein a vapor sensing device is disposed adjacent said vent pipe to detect escape of said volatile liquid.
 3. A vapor control system as set forth in claim 1 wherein the upper end of said vent pipe is provided with a generally inverted U-shaped fitting and said valve means is carried by said fitting.
 4. A vapor control system as set forth in claim 1 wherein the upper end of said vent pipe is disposed in a manhole and a vapor sensing device is positioned in said manhole adjacent said vent pipe to detect escape of said volatile liquid.
 5. A vapor control system as set forth in claim 4 wherein the upper end of said vent pipe is provided with a generally inverted U-shaped fitting and said valve means is carried by said fitting. 